The pillar of the crane (left) described is attached to the vessel. The slewing framework with the crane assembly is supported by the pillar. The bearing arrangement has to absorb the weight of the crane assembly and of the payload. Since the centre of gravity of payload and framework is offset from the pillar axis, a tilting moment is generated, resulting in horizontal reaction forces the upper and lower pillar bearings.
The upper pillar bearing arrangement features normally features a single Spherical Roller Thrust Bearing or a radial Spherical Roller Bearing combined with a Spherical Roller Thrust Bearing.
The type of bearing assembly selected depends on the magnitude of radial load. At the lower pillar end the gantry is supported by guiding rollers.